This disclosure relates to a multi-mode or dual mode electrical/chemical thruster for use in a propulsion system for a spacecraft where the thruster uses the same liquid monopropellant for operation in both modes. A propulsion system of this disclosure uses one or more of the above-said thrusters, which may be operated in either an electro-spray mode to achieve high specific impulse or in a chemical mode to achieve high thrust.
Most spacecraft propulsion concepts can be classified into two categories: chemical or electrical. Chemical propulsion relies on chemical reactions and can produce high thrust, but requires a relatively large amount of fuel. Electric propulsion uses electromagnetic fields to accelerate ionized gases and droplets. As compared to chemical propulsion, electric or electrospray propulsion is very fuel efficient and produces high specific impulse, but produces smaller amounts of thrust and thus requires long trip times. The propulsion system of the present disclosure relates to a thruster capable of switching between chemical mode and electric mode while utilizing the same propellant. Multiples of these thrusters may be combined to form a reaction control system or a propulsion system for a spacecraft. For propulsion applications in small satellites, minimum propulsion system mass is of utmost importance. The multi-mode propulsion system of the present disclosure makes use of shared propellant and shared hardware for operation in both the chemical and electric electrospray propulsive modes thus minimizing the mass of the propulsion system.
Ionic liquid multimode or dual mode propulsion systems are known, such as disclosed in WO 2010/036291, that employ an ionic liquid monopropellant, but require separate electrospray thrusters and chemical thrusters. The electrospray thrusters of such prior art systems are used for high specific impulse applications and the chemical thrusters are used for high thrust applications.